Air-brake for cars



rTED STATES PATENT OFFICE.

JOHN D. P. soHENoK, or NEWARK, NEW JERSEY.

AIR-'BRAKE 'll-'AOR CARS.

SEECIFICATION forming part of Letters Patent No. 532,914, dated January22, 1895. 'Application filed March 9, 1894. serial N o. 502,970.. or@modem .To @ZZ whom it may concern.-

Be it known that I, JOEND. P. SoHENoK, a citizen of the United States,residing at Newark, in the county of Essex and State of New Jersey, haveinvented certain new and use-4 ful Improvements in Air-Brakes for Cars,of which the following is a specification.

My present invention relates to air-brakes for railway trains, and hasreference particularly to that part of the brake-mechanism which isusually placed under the car-body.

The object cf the invention is to improve the construction of themechanism generally but in particular to provide for the quickevacuation of the air at the brake-cylinder when the brakes are beingset, all as will be here'- inafter fully explained with reference to theaccompanying drawings, and the novel features of the invention will becarefully defined in the claims.

In the said accompanying drawings--Figure 1 is a general view of thebraking-mechanism under a car and embodying my invention, thebrake-cylinder being represented in axial section. Fig. 2 is an enlargedaxial section of the relief device for effecting quick evacuation of theair. The plane of the section is indicated by line x, in Fig. l.

1 represents the train-pipe through whichA air under tension is suppliedto the brakecylinders under the respective cars of the train. I y

2 is the brake-cylinder, 3 the brake-piston therein, and 4 thepiston-rod, which will be coupled to the brake-levers` of the car intheusual way. These levers are not'shown asI they are well'known. n

When the brakes are off, the piston 3, will be in thev position seen inFig. 1; that is, Stopped by a prolongation, 5, of the piston-rod whichforms a distancing piece and which bears against the head of thebrake-cylinder. This stopping of the piston leaves a chamber, 6,'behindthe piston 3, and this chamber is connected by a pipe, 7, with anauxiliary airreservoir, 8. Thechamber 6, is also connected with thefront end of the brake-cylinder through a by-passage, 9, which opensinto the cylinder at 9X, just in front of the piston when the latter isin its extreme position seen in Fig. 1. The flow of air through thebypassage 9, is limited to one direction by a checkvalve 10, backed byalight spring of sufficient tension to keep the valve up to its seat.

v Vhen the engineer admits compressed air to the train-pipe 1, in orderto relieve the brakes, the air flows to the brake-cylinder 2, through arelief-device designated as a whole by A, in Fig. 1, and enters thefront end of the eylinder 2,at 2X. It presses back to the piston 3, tothe position seen in Fig. 1, and then flows through the by-passage 9, tothe chamber 6, displacing the valve, 10. From the chamber 6, it flows byway of pipe 7, to the reservoir 8, thus equalizing the tension in thesaid reservoir, the brake-cylinder, and the train-pipe. It will beobvious, however, that before the air can iiow through the by-passage 9,the piston 3, must be pressed or forced back to the stop so as touncover the entrance to Said passage.

When the engineer opens the train-pipe to the atmosphere to set thebrakes, the tension in the'brake-cylinder in front of the Vpiston is atonce reduced and as the check-valve 10, prevents the reflux of airthrough the bypassage 9, the tension behind the piston will force thepiston forward thus setting the brakes. n

Where a train is "long, as in the case of freight trains especially, itis found impossible to get that quick relief or evacuation of the air insetting the brakes which will enable the engineer to set the brakes onall of the cars at substantially thesame instant, Without employingrelieving devices at or near the point wherethe brakingv mechanism issituated on each car.' If the engineers valve alone be relied on forrelief, the air will not ow from the train-pipe quickly enough and thebrakes on the forward cars will be set an appreciable time before thoseon the rear cars.

The device A before referredto, has for its object to provide anautomatic vmeans for evac'uating the brake-cylinder directly by openingit to the atmospheretne instant the tension in the train-pipe isreduced, and also,

` should the engineer so desire, hemay so manipulate the engineers valveas to cause the evacuation of the train-pipe also atl this point. The`construction of this device will be described With reference to Fig. 2.'

11 is a casing having in it a cylindrical chamber, 12, which extendspart Way the length of the casing. In this chamber 12, plays a piston13, provided with a rod,14,

coupled to a slide-valve, 15, in a chamber,16.A

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The train-pipe 1, connects with the chamber 12, through a branch pipe1X, and passage 1a, and the brake-cylinder 2, connects with thevalve-chamber 16, through a pipe 2u. When the air under tension Iiowsfrom the trainpipe to thebrake-cylinder, it enters the chamber 12 at 1,flows into the chamber 16, through a by-passage, 17, around the piston13, and thence to the brake-cylinder by the pipe 2a. The by-passage17,is controlled by a checkvalve, 18, which prevents reiiux of air from thevalve-chamber 16.

The slide-valve 15, follows the movements of the piston 13, to and fro,and the operation is as follows: When the brakes are otf and the maximumair tension prevails in the brake-cylinder and train-pipe, there willbe, of course, an equal tension on both sides of the piston 13. If now,in setting the brakes, the engineer opens the engineers valve gradually,the tension will be relieved in chamber 12, and the piston 13, will bemoved as far as the dotted line y in chamber 12, thus shifting the valve15, far enough to uncover a port, 19, in the casing 11, and opening thevalvechamber 16, to the atmosphere. This will evacuate the brake-ey1nder2, instantly and set the brakes on this car.

The dotted line y corresponds to the end of a coil spring, 20, coiledabout a tubular socket, 21, in the chamber 12, and this spring willarrest the piston in its movement under the conditions named; but if theengineer opens his valve fully and suddenly, the tension in thevalve-chamber 16, will act so forcibly on the piston 13, as to cause itto move on until it is stopped by the end of the guide 21, the spring 2Oyielding to perlnit of this further movement of the piston. Under theseconditions the valve l5, will be carried on until a passage, 22, fromthe train-pipe inlet, 1a, will be opened to a port, 23, leading to theatmosphere, through the medium of a recess, 24, in the valve 15, and thetrain-pipe will be evacuated simultaneously with the brake-cylinder,thus relieving the train-pipe at each car simultaneously no matter howmany cars may be in the train. This opening of the train-pi pe will,however,

only be momentary as the recoil of the spring 20,will drive back thepiston to the line y and cause the valve to close the ports 23, as soonas the tension behind the piston 13, is relieved. If the piston remainsat the point indicated by the line y and air under tension be admittedby the train-pipe to release the brakes, it cannot flow through theby-passage 17, about the piston until the latter is moved far enough touncover the port from the chamber 12, to the said by-passage, and whenthe piston is so moved, it will shift the valve far enough to close theport 19, which opens the valve-chamber to the atmosphere. Thus theengineer may, if he so desires, simply evacuate the air from thebrake-cylinders or, at will, evacuate also the train-pipe at each car.

Having thus described my invention, I claim-- 1. In an air-brake forears, the combination with the train-pipe and brake-cylinder, of adevice for directly evacuating the train-pipe at each car of the train,when the brakes are set, by opening said pipe automatically to theatmosphere, said device comprising as its essentials a casing having init a cylindrical piston-chamber opento the trainpipe, a valvechamberopen to the cylinder, a port leading tothe atmosphere from thevalve-chamber, and a passage connecting the valve-chamber with thetrain-pipe, a piston in the pistonchamber, a pistonrod extending fromthe piston into the valve-chamber, and a valve in said chamber coupledto the piston-rod and controlling the port leading to the atmosphere andthe passage leading to the trainpipe, substantially as and for thepurposes set forth.

2. In an air-brake for cars, the combination with the train-pipe andbrake-cylinder, of a device for effecting the evacuation of thebrake-cylinder to the atmosphere at each car,

said device comprising a casing having a piston-chan1ber 12, at one end,in communication with the train-pipe, a valve-chamber 16, at the otherend in communication with the brake-cylinder, and a port leading fromthe valve-chamber to the atmosphere, a pistonin the piston-chamberbetween the inlets from the train-pipe and brake-cylinder, the rod ofsaid piston, extending into the valve-chamber, a valve in said chambercontrolling the port to the atmosphere, a by-passage 17, connecting thepiston-ehamber and valve-chamber and openinginto the latterbehind thepiston when the brakes are off, and a valve 18, controlling saidby-passage and preventing the iiow of air therethrough from thevalvechamber to the piston-chamber, substantially as set forth.

3. In an air-brake for cars, the combination with the train-pipe and thebrakecylinder, of a device arranged between the said pipe and cylinderfor the direct evacuation of the air in setting the brakes, said devicecomprising a casing 11, connected with the train-pipe at one end andwith the brake-cylinder at the other end, a piston 13 in said casingbetween the said connecting points, a valve 15, in the casing adjacentto the inlet from the brakecylinder, said valve controlling a port 19,to the atmosphere, and having a recess 24, adapted to connect a port 23,to the atmosphere with a port-passage 22, open to the train-pipe, acushion spring 20, in the end of the casing adjacent to the train-pipeinlet, a by-passage 17, about the piston, and a check-valve in saidby-passage to prevent the reflux of air, said ports being arranged tooperate substantially as set forth.

In witness whereof I have hereunto signed my name in the presence of twosubscribing Witnesses.

JOHN D. P. SCHENCK.

"Witnesses:

PETER A. Ross, J As. KING DUFFY.

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